U.S. patent application number 15/389346 was filed with the patent office on 2017-04-13 for spinal implants and related instruments and methods.
The applicant listed for this patent is Amedica Corporation. Invention is credited to Stephen P. Brown, Chad Wayne Lewis, Jared M. White.
Application Number | 20170100259 15/389346 |
Document ID | / |
Family ID | 52740894 |
Filed Date | 2017-04-13 |
United States Patent
Application |
20170100259 |
Kind Code |
A1 |
Brown; Stephen P. ; et
al. |
April 13, 2017 |
SPINAL IMPLANTS AND RELATED INSTRUMENTS AND METHODS
Abstract
Apparatus and systems relating to spinal implants and
instruments for installing such implants. In some embodiments, the
system may comprise a spinal implant, an inserter, an intermediary
piece, and/or an installation rod. The spinal implant may comprise
an at least partially threaded opening configured to receive the
installation rod. The opening may be positioned within a fixed wall
of the spinal implant, and the opening may comprise a peripheral
edge defined by the wall of the spinal implant.
Inventors: |
Brown; Stephen P.; (South
Jordan, UT) ; White; Jared M.; (Draper, UT) ;
Lewis; Chad Wayne; (Erie, CO) |
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Applicant: |
Name |
City |
State |
Country |
Type |
Amedica Corporation |
Salt Lake City |
UT |
US |
|
|
Family ID: |
52740894 |
Appl. No.: |
15/389346 |
Filed: |
December 22, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14500671 |
Sep 29, 2014 |
9526629 |
|
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15389346 |
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61883687 |
Sep 27, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2/4611 20130101;
A61F 2002/4627 20130101; A61F 2002/30904 20130101; A61F 2002/30112
20130101; A61F 2002/4629 20130101; A61F 2/4465 20130101; A61F
2002/3082 20130101; A61F 2002/30784 20130101 |
International
Class: |
A61F 2/44 20060101
A61F002/44; A61F 2/46 20060101 A61F002/46 |
Claims
1. A spinal implant, comprising: a first sidewall; a second
sidewall opposite from the first sidewall; an upper surface
configured for engaging a first vertebra; a lower surface
configured for engaging a second vertebra adjacent to the first
vertebra; a first end wall joining the first sidewall and the
second sidewall at a first end of the spinal implant; a second end
wall joining the first sidewall and the second sidewall at a second
end of the spinal implant opposite from the first end, wherein the
second end wall defines a second end wall surface; at least one of
a recess and a protrusion formed in the second end wall; and an
opening positioned within the second end wall, wherein the opening
comprises a threaded region formed within an integral portion of
the spinal implant so as to be fixed relative to the second end
wall, wherein the opening is defined by an external peripheral edge
formed in the second end wall of the spinal implant and by an
internal peripheral edge opposite from the external peripheral
edge, wherein the threaded region is spaced apart from the second
end wall surface, wherein the threaded region is spaced apart from
the external peripheral edge and internal to the external
peripheral edge, and wherein the threaded region is spaced apart
from the internal peripheral edge such that the threaded region is
spaced apart from both opposing ends of the opening.
2. The spinal implant of claim 1, wherein the spinal implant
further comprises an expanded region within the opening.
3. The spinal implant of claim 2, wherein the expanded region
comprises a diameter greater than a diameter of at least a portion
of the opening adjacent to the expanded region, and wherein the
expanded region is configured to provide clearance for threads on a
threaded section of an installation rod.
4. The spinal implant of claim 2, wherein the expanded region is
defined by a frustoconical shape that tapers so as to expand the
diameter of the opening towards a proximal end of the opening.
5. The spinal implant of claim 1, wherein the spinal implant
further comprises notches formed in the upper surface and the lower
surface of a nose at least partially defined by the first end
wall.
6. The spinal implant of claim 1, wherein the spinal implant
further comprises at least one fin positioned along a peripheral
edge of at least one of the first and second sidewalls.
7. The spinal implant of claim 6, wherein the at least one fin
comprises a partial fin that extends only along a peripheral edge
of a nose of the spinal implant at least partially defined by the
first end wall.
8. The spinal implant of claim 6, wherein the at least one fin
comprises a first fin formed on the upper surface and a second fin
formed on the lower surface.
9. The spinal implant of claim 1, wherein the at least one of a
recess and a protrusion formed in the second end wall comprises a
v-shaped recess.
10. The spinal implant of claim 9, wherein the v-shaped recess is
spaced apart from the first sidewall and the second sidewall.
11. A spinal implant system, comprising: a spinal implant
comprising an at least partially threaded opening configured to
receive an installation rod for installing the spinal implant
within an intervertebral space of a patient, wherein the opening is
positioned within a fixed wall of the spinal implant, and wherein
the opening comprises a peripheral edge defined by the wall of the
spinal implant; an inserter configured to receive an installation
rod therethrough; an intermediary piece configured to be coupled
with the spinal implant and the inserter in between the spinal
implant and a distal end of the inserter, wherein the intermediary
piece is configured to receive an installation rod therethrough,
wherein the intermediary piece comprises at least one of a
protrusion and a recess configured to engage at least one of a
recess and a protrusion formed in the spinal implant; and an
installation rod configured to be positioned within the opening,
wherein the installation rod comprises an engagement section
configured to engage a portion of the spinal implant defining the
opening at a location internal to the peripheral edge such that the
highest forces applied to the spinal implant in coupling the spinal
implant with the installation rod during installation of the spinal
implant are not applied to the portion of the opening defined by
the peripheral edge.
12. The spinal implant system of claim 11, wherein the installation
rod comprises a threaded section configured to engage the opening
at a location spaced apart from the peripheral edge.
13. The spinal implant system of claim 12, wherein the spinal
implant further comprises an expanded region within the opening
extending from the peripheral edge, wherein the expanded region
comprises a diameter greater than a diameter of at least a portion
of the opening adjacent to the expanded region, and wherein the
expanded region is configured to provide clearance for threads on
the threaded section of the installation rod.
14. The spinal implant system of claim 11, wherein the spinal
implant further comprises a fin extending along an upper surface of
the spinal implant.
15. The spinal implant system of claim 14, wherein the spinal
implant comprises a convex side wall surface, and wherein the fin
is positioned adjacent to the convex side wall surface.
16. The spinal implant system of claim 14, wherein the spinal
implant further comprises a second fin extending along a lower
surface of the spinal implant adjacent to the convex side wall
surface.
17. A spinal implant system, comprising: a spinal implant
comprising an opening configured to receive an installation rod for
installing the spinal implant within an intervertebral space of a
patient, wherein the opening is positioned within a fixed wall of
the spinal implant, and wherein the opening comprises a peripheral
edge defined by the wall of the spinal implant; and an installation
rod configured to be positioned within the opening, wherein the
installation rod comprises a threaded section and an engagement
section configured to engage a portion of the spinal implant
defining the opening at a location internal to the peripheral edge
such that the highest forces applied to the spinal implant in
coupling the spinal implant with the installation rod during
installation of the spinal implant are not applied to the portion
of the opening defined by the peripheral edge, wherein the opening
is at least partially threaded, wherein the spinal implant further
comprises an expanded region within the opening extending from the
peripheral edge, wherein the expanded region comprises a diameter
greater than a diameter of at least a portion of the opening
adjacent to the expanded region, and wherein the expanded region is
configured to provide clearance for threads on the threaded section
of the installation rod.
18. The spinal implant system of claim 17, wherein the threaded
section is configured to engage the opening at a location spaced
apart from the peripheral edge.
19. The spinal implant system of claim 17, wherein the spinal
implant further comprises an expanded region within the opening,
wherein the expanded region comprises a diameter greater than a
diameter of at least a portion of the opening adjacent to the
expanded region, and wherein the expanded region is configured to
provide clearance for threads on the threaded section of the
installation rod.
20. The spinal implant system of claim 17, wherein the installation
rod further comprises: a first unthreaded section positioned
adjacent to and distally of the threaded section; and a second
unthreaded section positioned adjacent to and proximally of the
threaded section, wherein the first unthreaded section and the
second unthreaded section both comprise a diameter less than a
major diameter of the threads of the threaded section.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of co-pending U.S. patent
application Ser. No. 14/500,671, filed on Sep. 29, 2014, and titled
"SPINAL IMPLANTS AND RELATED INSTRUMENTS AND METHODS," which claims
the benefit under 35 U.S.C. .sctn.119(e) of U.S. Provisional Patent
Application 61/883,687 filed Sep. 27, 2013 and titled "SPINAL
IMPLANTS AND RELATED INSTRUMENTS AND METHODS." Both of the
aforementioned applications are hereby incorporated by reference
herein in their entireties.
SUMMARY
[0002] Disclosed herein are embodiments of systems, apparatus, and
methods that relate to spinal implants and instruments for
installing such implants. In some embodiments, the implants and
related instrumentation may be configured to reduce or eliminate
the forces applied to relatively weak portions of the implant, with
may be at the peripheral edge(s)/end(s) of an opening/hole in the
implant for receiving an instrument, such as a rod. Thus, some
embodiments may be configured such that the highest forces applied
to an engagement region in the implant, such as threads in the
spinal implant, will be applied to the strongest area and/or
threads of the implant. This may substantially reduce fractures or
other damage that may otherwise be prone to occur, particularly
with respect to certain ceramic spinal implants.
[0003] In a more particular example of a spinal implant system, the
system may comprise a spinal implant comprising a first sidewall, a
second sidewall opposite from the first sidewall, an upper surface
configured for engaging a first vertebra, and a lower surface
configured for engaging a second vertebra adjacent to the first
vertebra. The spinal implant may further comprise a first end wall
joining the first sidewall and the second sidewall at a first end
of the spinal implant, and a second end wall joining the first
sidewall and the second sidewall at a second end of the spinal
implant opposite from the first end. The second end wall may define
a second end wall surface.
[0004] At least one of a recess and a protrusion may be formed in
the second end wall, and an opening may be positioned within the
second end wall. In some embodiments, a v-shaped recess may be
provided. In some embodiments, the recess/protrusion may be spaced
apart from the opposing sidewalls such that it only extends
partially across a rear surface of the implant. Alternatively, the
recess/protrusion may extend all of the way across an end of the
implant so as to extend from one sidewall to the opposite sidewall.
The opening may comprise a threaded region, and wherein the
threaded region is spaced apart from the second end wall
surface.
[0005] The system may further comprise an installation rod
configured to be positioned within the opening. The installation
rod may comprise a threaded section configured to engage the
threaded region of the opening at a location spaced apart from the
second end wall surface.
[0006] Some embodiments may further comprise an inserter comprising
an opening configured to receive the installation rod therethrough.
Some embodiments may further comprise an intermediary piece
configured to be coupled with the spinal implant and the inserter
in between the spinal implant and the inserter. The intermediary
piece may comprise at least one of a recess and a protrusion
configured to engage the at least one of a recess and a protrusion
formed in the second end wall of the spinal implant.
[0007] In some embodiments, the spinal implant may further comprise
an expanded region within the opening. The expanded region may be
configured to accommodate an engagement feature of the installation
rod, such as threads. Thus, the expanded region may comprise a
diameter greater than a diameter of at least a portion of the
opening adjacent to the expanded region, and may be configured to
provide clearance for threads on the threaded section of the
installation rod. In some embodiments, the expanded region may be
defined by a frustoconical shape that tapers so as to expand the
diameter of the opening towards a proximal end of the opening.
[0008] The installation rod may also, or alternatively, be
configured to allow for coupling between the implant and the rod
and preferred locations in order to reduce the likelihood of
breakage. For example, in some embodiments, the rod may comprise
one or more reduced diameter sections positioned adjacent to the
threaded section. The reduced diameter section(s) may comprise a
diameter less than a diameter of the threads of the threaded
section of the rod.
[0009] A reduced diameter section may be positioned adjacent to and
distally of the threaded section, and the reduced diameter section
may comprise a diameter less than a minor diameter of the threads
of the threaded section. Another reduced diameter section, or an
alternative reduced diameter section, may be positioned adjacent to
and proximally of the threaded section, in order to facilitate a
desired coupling.
[0010] In some embodiments, the installation rod may further
comprise a knob positioned adjacent to the reduced diameter
section. The knob may comprise a diameter greater than the diameter
of the reduced diameter section. The opening in the spinal implant
may extend all of the way through the second end wall so as to
define a passageway, and, in some such embodiments, the knob may be
configured such that at least a portion of the knob extends all of
the way through the passageway when the installation rod is coupled
with the spinal implant. The knob may, in some embodiments,
comprise a flexible material such that the knob compresses as the
knob extends through the passageway and at least a portion of the
knob expands after extending through the passageway.
[0011] The spinal implant may further comprise notches formed in
the upper surface and the lower surface of a nose at least
partially defined by the first end wall, which may allow the shape
of the nose and/or adjacent sidewalls to guide the spinal implant
in a desired manner during installation. In some embodiments, the
spinal implant may further comprise a pair of fins positioned along
a peripheral edge of at least one of the first and second
sidewalls, which may further, or as an alternative, provide such
desired guidance during installation. The fins may comprise partial
fins that extend only along a peripheral edge of a nose of the
spinal implant at least partially defined by the first end wall.
Alternatively, the fins may extend all of the way, or at least
substantially the entire way, along one or both sidewalls of the
implant.
[0012] In another particular example of a spinal implant system,
the system may comprise a spinal implant comprising an opening
configured to receive an installation rod for installing the spinal
implant within an intervertebral space of a patient. The opening
may be positioned within a wall of the spinal implant, and the
opening may comprise a peripheral edge defined by the wall of the
spinal implant.
[0013] The system may further comprise an installation rod
configured to be positioned within the opening. The installation
rod may comprise an engagement section configured to engage a
portion of the spinal implant defining the opening at a location
spaced apart from the peripheral edge such that the highest forces
applied to the spinal implant in coupling the spinal implant with
the installation rod during installation of the spinal implant are
not applied to the portion of the opening defined by the peripheral
edge.
[0014] In some embodiments, the opening may be at least partially
threaded, and the installation rod may comprise a threaded section
configured to engage the opening at a location spaced apart from
the peripheral edge.
[0015] In some embodiments, the spinal implant may further comprise
an expanded region within the opening. The expanded region may
comprise a diameter greater than a diameter of at least a portion
of the opening adjacent to the expanded region, and may be
configured to provide clearance for threads on the threaded section
of the installation rod.
[0016] The installation rod may comprise a first unthreaded section
positioned adjacent to and distally of the threaded section and/or
a second unthreaded section positioned adjacent to and proximally
of the threaded section. The first unthreaded section and the
second unthreaded section may both comprise a diameter less than a
major diameter of the threads of the threaded section. In some
embodiments, one or both of the unthreaded sections may comprise a
diameter less than a minor diameter of the threads of the threaded
section.
[0017] In another particular example of a spinal implant system,
the system may comprise a spinal implant comprising a first
sidewall, a second sidewall opposite from the first sidewall, an
upper surface configured for engaging a first vertebra, and a lower
surface configured for engaging a second vertebra adjacent to the
first vertebra. At least one opening may extend between the upper
surface and the lower surface.
[0018] A first end wall may join the first sidewall and the second
sidewall at a first end of the spinal implant, and a second end
wall may join the first sidewall and the second sidewall at a
second end of the spinal implant opposite from the first end. The
second end wall may define a second end wall surface. At least one
of a recess and a protrusion may be formed in the second end wall,
and may be configured to engage a corresponding protrusion or
recess of a spinal installation instrument.
[0019] A hole may be positioned in the at least one of a recess and
a protrusion in the second end wall. The hole may extend through
the second end wall and into the at least one opening, and may be
configured to receive an installation rod for installing the spinal
implant within an intervertebral space of a patient. The hole may
comprise a threaded region that may be spaced apart from the second
end wall surface and/or may be spaced apart from an end of the hole
opposite from the second end wall surface. The hole may further
comprise an expanded region adjacent to the second end wall surface
that may have a diameter greater than a diameter of at least a
portion of the hole adjacent to the expanded region, which may
allow for accommodating the threads during coupling of the implant
and the rod.
[0020] The system may further comprise a spinal installation
instrument, which may comprise an inserter and an intermediary
piece configured to be coupled with the spinal implant and the
inserter in between the spinal implant and the inserter, both of
which may be configured to receive an installation rod
therethrough, such as by way of a contiguous opening through the
inserted and intermediary piece. The intermediary piece may
comprise at least one of a protrusion and a recess configured to
engage the at least one of a recess and a protrusion formed in the
second end wall of the spinal implant.
[0021] The spinal installation instrument may further comprise an
installation rod configured to be positioned within and extend
through the inserter and the intermediary piece. The installation
rod may comprise a threaded section configured to engage the
threaded portion of the spinal implant at a location spaced apart
from both opposite ends of the hole. The expanded region of the
spinal implant may be configured to provide clearance for threads
on the threaded section. The installation rod may further comprise
at least one unthreaded section positioned adjacent to the threaded
section, which may have a diameter less than a major diameter of
the threads of the threaded section.
[0022] The features, structures, steps, or characteristics
disclosed herein in connection with one embodiment may be combined
in any suitable manner in one or more alternative embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The written disclosure herein describes illustrative
embodiments that are non-limiting and non-exhaustive. Reference is
made to certain of such illustrative embodiments that are depicted
in the figures, in which:
[0024] FIG. 1 is a perspective view of a spinal implant according
to one embodiment.
[0025] FIG. 2 is a top plan view of the spinal implant of FIG.
1.
[0026] FIG. 3 is a cross-sectional view of the spinal implant of
FIGS. 1 and 2.
[0027] FIG. 4 is a perspective view of a spinal implant according
to another embodiment.
[0028] FIG. 5 is a top plan view of the spinal implant of FIG.
4.
[0029] FIG. 6 is a cross-sectional view of the spinal implant of
FIGS. 4 and 5.
[0030] FIG. 7 is a perspective view of a spinal implant according
to yet another embodiment.
[0031] FIG. 8 is a top plan view of the spinal implant of FIG.
7.
[0032] FIG. 9 is a cross-sectional view of the spinal implant of
FIGS. 7 and 8.
[0033] FIG. 10 is a perspective view of a spinal implant according
to still another embodiment.
[0034] FIG. 11 is a top plan view of the spinal implant of FIG.
10.
[0035] FIG. 12 is a cross-sectional view of the spinal implant of
FIGS. 10 and 11.
[0036] FIG. 13 is a perspective view of yet another embodiment of a
spinal implant.
[0037] FIG. 14 is a top plan view of the spinal implant of FIG.
13.
[0038] FIG. 15 is a perspective view of still another embodiment of
a spinal implant.
[0039] FIG. 16 is a top plan view of the embodiment of FIG. 15.
[0040] FIG. 17 depicts an embodiment of an installation rod
configured to be positioned within certain embodiments of surgical
instruments for installing spinal implants.
[0041] FIG. 18 is a close-up view of the distal end of the
installation rod of FIG. 17 that is configured to interface with a
spinal implant.
[0042] FIG. 19 depicts embodiments of a spinal implant, an
inserter, and an intermediary piece each positioned in engagement
with one another and specifically depicting the interface between
the installation rod of FIG. 17 and a spinal implant.
[0043] FIG. 20 depicts alternative embodiments of a spinal implant,
an inserter, and an intermediary piece each positioned in
engagement with one another.
[0044] FIG. 21 depicts other embodiments of a spinal implant, an
inserter, and an intermediary piece each positioned in engagement
with one another.
[0045] FIG. 22 is a partial, cross-sectional view of three
embodiments of spinal implants each having different sizes and
different inserter hole angles.
[0046] FIG. 23 is cross-sectional view of still other alternative
embodiments of a spinal implant, an inserter, and an intermediary
piece each positioned in engagement with one another.
[0047] FIG. 24 is a perspective view of a spinal implant according
to still another embodiment.
DETAILED DESCRIPTION
[0048] A detailed description of apparatus, systems, and methods
consistent with various embodiments of the present disclosure is
provided below. It will be readily understood that the components
of the present disclosure, as generally described and illustrated
in the drawings herein, could be arranged and designed in a wide
variety of different configurations. Thus, the following more
detailed description of the embodiments of the apparatus is not
intended to limit the scope of the disclosure, but is merely
representative of possible embodiments of the disclosure. In
addition, while numerous specific details are set forth in the
following description in order to provide a thorough understanding
of the embodiments disclosed herein, some embodiments can be
practiced without some or all of these details. Moreover, for the
purpose of clarity, certain technical materials, structures, or
operations that are known in the related art have not been shown or
described in detail in order to avoid unnecessarily obscuring the
disclosure.
[0049] Various embodiments of apparatus, methods, and systems are
disclosed herein that relate to spinal implants and instruments for
installing such implants. For example, some embodiments may
comprise intervertebral spinal spacers. Some embodiments may
comprise instruments for installing such intervertebral spinal
implants and/or intermediary pieces configured for being positioned
between an inserter and a spinal implant.
[0050] Some embodiments may be particularly useful for spinal
implants comprising a ceramic material, such as a silicon nitride
ceramic material. Examples of suitable silicon nitride materials
are described in, for example, U.S. Pat. No. 6,881,229, titled
"Metal-Ceramic Composite Articulation," which is incorporated by
reference herein. In some embodiments, dopants such as alumina
(Al.sub.2O.sub.3), yttria (Y.sub.2O.sub.3), magnesium oxide, and
strontium oxide, can be processed to form a doped composition of
silicon nitride. In some embodiments, powders of silicon nitride
may be used to form the ceramic implants, either alone or in
combination with one or more of the dopants referenced above. Other
examples of suitable silicon nitride materials are described in
U.S. Pat. No. 7,666,229 titled "Ceramic-Ceramic Articulation
Surface Implants," which is also hereby incorporated by reference.
Still other examples of suitable silicon nitride materials are
described in U.S. Pat. No. 7,695,521 titled "Hip Prosthesis with
Monoblock Ceramic Acetabular Cup," which is also hereby
incorporated by reference. However, it should be understood that
many of the inventive concepts and principles disclosed herein can
be applied to implants comprising any materials known or hereafter
developed, including, for example, titanium, titanium alloys,
steel, polymers, poly-ether-ether-ketone (PEEK), bone graft,
biological compounds, other ceramics/composites, and the like.
[0051] Additional details regarding certain preferred embodiments
will now be described in greater detail with reference to the
accompanying drawings. FIG. 1 depicts a perspective view of an
embodiment of a spinal implant 100. Spinal implant 100 comprises an
upper surface 102, a lower surface 104, a first side wall surface
106, a second side wall surface 108 opposite from surface 106, a
front end wall surface 110 comprising a nose 111, and a rear end
wall surface 112 opposite from front end wall surface 110
comprising a recess 130. Recess 130 comprises a v shape that may be
configured to directly interface with a spinal installation
instrument or to indirectly couple with an intermediary piece
configured to directly interface with such an instrument.
[0052] Upper and lower surfaces 102 and 104 may both comprise a
plurality of engagement structures 120, which in the depicted
embodiment comprise rows of teeth. Teeth 120 are arranged in rows
and radiate from a focal point positioned along the axis of spinal
implant 100. Spinal implant 100 and its axis extend along an
arcuate path to form a shape substantially in the form of a kidney.
More particularly, first side wall surface 106 is concave and
second side wall surface 108 is convex to form the kidney-like
shape.
[0053] Each of the rows in which teeth 120 are arranged is at least
substantially perpendicular to both the first side wall surface 106
and the second side wall surface 108. In addition, in the depicted
embodiment, the spacing between the rows of teeth decreases from
the front end wall surface 110 or nose 111 to the rear end wall
surface 112.
[0054] Upper surface 102 also comprises an opening 122, as shown in
FIG. 2. As best shown in the upper plan view of FIG. 2, opening 122
also extends through lower surface 104 to allow for ingrowth of
bony material therethrough. Portions of the inner surface of
opening 122, along with side wall surfaces 106 and 108, form walls
or rails 123 that extend along the periphery of spinal implant
100.
[0055] As illustrated in FIG. 1, and in the cross-sectional view of
FIG. 3, openings 124 are also formed in side wall surfaces 106 and
108. Of course, alternative embodiments are contemplated in which
differing numbers and/or shapes of side wall, top surface, and/or
lower surface openings are formed as desired. For example, in some
embodiments that may be designed as lordotic spinal implants, the
implant may be sloped from one lateral side to the opposite lateral
side. In some such embodiments, it may be useful to provide side
wall openings that are larger on the side of the implant having the
greatest height (typically the anterior side) and smaller openings
in the side of the implant having the smallest height (typically
the posterior side).
[0056] Rear end wall surface 112 forms a recessed area 130 formed
into the shape of a fishtail. Recess 130 may be configured to
engage a corresponding surface of an inserter tool, as discussed in
greater detail below. Moreover, as also shown in FIG. 1, and in the
cross-sectional view of FIG. 3, spinal implant 100 may have an
opening 140 formed in recessed area 130 of rear end wall surface
112. In some embodiments, opening 140 may be threaded so as to
allow for engagement with an inserter tool. In some embodiments,
other retention structures may be used to facilitate engagement
between spinal implant 100 and an installation rod or other
inserter instrumentation. Although in the depicted embodiment,
opening 140 extends all of the way through the rear wall defining
rear end wall surface 112, alternative embodiments are contemplated
in which opening 140 comprises a blind hole.
[0057] In some embodiments, such as the embodiment depicted in FIG.
1, opening 140 may be formed within a central region of recess 130.
In the embodiment depicted in FIGS. 1-3, it can also be seen that
opening 140 extends along the arcuate axis of spinal implant 100.
However, as discussed below in connection with other figures, other
embodiments are contemplated in which the inserter opening does not
extend along this axis.
[0058] Nose 111 tapers as it extends from side wall surfaces 106
and 108 to the tip of the implant. This taper may extend along both
the upper surface 102 and the lower surface 104 of the implant such
that nose 111 is thinner than the rest of spinal implant 100.
[0059] In the depicted embodiment, a notch 115 is also formed in
the material defining nose 111 adjacent to opening 122. In some
embodiments, notch 115 may comprise a groove. Although not visible
in the figures, in preferred embodiments, a corresponding notch may
also be formed in the opposite surface of nose 111 (adjacent to
lower surface 104) in a similar manner. It has been discovered that
one or more such notches may be beneficial in allowing rails/walls
123 to serve as a guide rail to guide spinal implant 100 in a
desired path during a surgical procedure to install implant 100 in
a patient's intervertebral space. In embodiments lacking such
notches 115, the nose 111 may undesirably hinder the ability of
rails/walls 123 to guide or curve the implant 100 during
installation.
[0060] As also shown in the figures (best shown in FIG. 1), in some
embodiments notch 115 may be formed directly in one or both of the
tapered surfaces (upper and lower) of nose 111. As also shown in
the figures, notch 115 extends from the peak of a tooth 120 on one
side of implant 100 to a tooth 120 in the same row on the opposite
side of implant 100.
[0061] FIG. 4 is a perspective view of another embodiment of a
spinal implant 200 (with other views depicted in FIGS. 5 and 6).
Like spinal implant 100, spinal implant 200 comprises an upper
surface 202, a lower surface 204, a first side wall surface 206, a
second side wall surface 208 opposite from surface 206, a front end
wall surface 210 comprising a nose 211, and a rear end wall surface
212 opposite from front end wall surface 210. However, rear end
wall surface 212 comprises a protrusion 230 rather than a recess.
Protrusion 230 comprises a v shape that protrudes from rear end
wall surface 212. Like the v-shaped recess 130 of spinal implant
100, v-shaped protrusion 230 may be configured to directly
interface with a spinal installation instrument or to indirectly
couple with an intermediary piece configured to directly interface
with such an instrument.
[0062] Upper and lower surfaces 202 and 204 both comprise a
plurality of teeth 220 arranged in rows. Teeth 220 radiate from a
focal point positioned along the axis of spinal implant 200.
However, in other embodiments comprising such teeth, they may be
instead arranged in parallel rows. Spinal implant 200 and its axis
extend along an arcuate path to form a kidney shape. Each of the
rows in which teeth 220 are arranged is at least substantially
perpendicular to both the first side wall surface 206 and the
second side wall surface 208. In addition, like the embodiment of
FIGS. 1-3, the spacing between the rows of teeth decreases from the
front end wall surface 210 and/or nose 211 to the rear end wall
surface 212.
[0063] Upper surface 202 also comprises an opening 222 that extends
through lower surface 204 to allow for ingrowth of bony material
therethrough. Portions of the inner surface of opening 222, along
with side wall surfaces 206 and 208, form walls or rails 223 that
extend along the periphery of spinal implant 200. Openings 224 are
also formed in side wall surfaces 206 and 208.
[0064] As shown in FIG. 4, spinal implant 200 also comprises an
opening 240 formed in one of the two surfaces forming v-shaped
protrusion 230. It should be understood, however, that a wide
variety of alternative embodiments are contemplated in which
alternative shapes/structures are formed on one or both of the end
wall surfaces of the implant. For example, some embodiments may
comprise a u-shaped protrusion, a u-shaped recession, or any other
shape, geometry, and/or feature that serves to prevent or at least
inhibit rotation between an inserter and the implant. Still other
embodiments may lack any such shape, geometry, or feature if
desired.
[0065] In some embodiments, opening 240 may be threaded so as to
allow for engagement with an inserter tool. Opening 240 does not
extend along the arcuate axis of spinal implant 200. More
specifically, opening 240 is positioned at an angle of about 20
degrees with respect to the arcuate axis of spinal implant 200. In
some embodiments, the angle at which the opening is formed with
respect to the axis of the implant may be between about 10 degrees
and about 45 degrees. In some such embodiments, the angle at which
the opening is formed with respect to the axis of the implant may
be between about 15 degrees and about 30 degrees. The surface of
v-shaped protrusion 230 in which opening 240 is formed may
therefore also be angled with respect to the axis of implant 200 at
this angle. This angling may be useful for certain applications,
and for use in connection with certain inserters. For example,
angling the inserter hole may be useful for positioning spinal
implant 200 at a desired angle during an installation surgery.
[0066] It can also be seen that opening 240 is not only formed at
an angle with respect to the axis of implant 200, but it also
begins at a location offset from (below from the perspective of the
cross-sectional view of FIG. 6) this axis.
[0067] Like spinal implant 100, spinal implant 200 also comprises a
nose 211 that tapers as it extends from side wall surfaces 206 and
208 to the tip of the implant along both the upper surface 202 and
the lower surface 204 of the implant. Spinal implant 200 further
comprises notches 215 formed in both opposite surfaces of nose 211.
As mentioned above, this feature may be useful in allowing the
sidewalls/rails 223 of implant 200 to be used to guide implant 200
in a curved path as the implant 200 is installed in a patient's
intervertebral space.
[0068] FIG. 7 is a perspective view of a spinal implant 300
according to yet another embodiment. FIG. 8 is a top plan view of
spinal implant 300, and FIG. 9 is a cross-sectional view of spinal
implant 300. Like spinal implants 100 and 200, spinal implant 300
comprises an upper surface 302, a lower surface 304, a first side
wall surface 306, a second side wall surface 308 opposite from
surface 306, a front end wall surface 310 comprising a nose 311,
and a rear end wall surface 312 opposite from front end wall
surface 310.
[0069] Rear end wall surface 312 comprises a recess 330, similar to
recess 130 of spinal implant 100. Recess 330 comprises a v shape
formed in a fishtail configuration that may be configured to
directly interface with a spinal installation instrument or to
indirectly couple with an intermediary piece configured to directly
interface with such an instrument. Spinal implant 300 also
comprises an opening 340 formed in v-shaped recess 330. In some
embodiments, opening 340 may be threaded so as to allow for
engagement with an inserter tool.
[0070] However, unlike spinal implant 100, opening 340 does not
extend along the arcuate axis of spinal implant 300. More
specifically, opening 340 is positioned at an angle with respect to
the arcuate axis of spinal implant 300. In some embodiments, the
angle at which the opening is formed with respect to the axis of
the implant may be between about 10 degrees and about 45 degrees.
In some such embodiments, the angle at which the opening is formed
with respect to the axis of the implant may be between about 15
degrees and about 30 degrees. This angling may be useful for
certain applications, and for use in connection with certain
inserters. For example, angling the inserter hole may be useful for
positioning spinal implant 300 at a desired angle during an
installation surgery.
[0071] It can also be seen in FIG. 9 that, unlike spinal implant
200, although opening 340 extends at an angle with respect to the
arcuate angle of spinal implant 300, opening 340 begins at a
location coincident with this axis. In other words, opening 340 is
formed at a midpoint of recess 330, which is along the arcuate axis
of implant 300, but then extends at an angle (upward from the
perspective of FIG. 9) from this arcuate axis. It can also be seen
from FIG. 9 that opening 340 extends into opening 322. However,
alternative embodiments are contemplated in which opening 340 may
form a blind hole that is closed at one end and does not extend
into opening 322 (or another similar opening) of implant 300.
[0072] Like implants 100 and 200, upper and lower surfaces 302 and
304 of implant 300 both comprise a plurality of teeth 320 arranged
in rows. Teeth 320 radiate from a focal point positioned along the
axis of spinal implant 300. In addition, spinal implant 300 and its
axis extend along an arcuate path to form a kidney shape. Each of
the rows in which teeth 320 are arranged is at least substantially
perpendicular to both the first side wall surface 306 and the
second side wall surface 308. In addition, like the embodiments
depicted in the previous figures, the spacing between the rows of
teeth decreases from the front end wall surface 310 or nose 311 to
the rear end wall surface 312.
[0073] Upper surface 302 also comprises an opening 322 that extends
through lower surface 304 to allow for ingrowth of bony material
therethrough. Portions of the inner surface of opening 322, along
with side wall surfaces 306 and 308, form walls or rails 323 that
extend along the periphery of spinal implant 300. Openings 324 are
also formed in side wall surfaces 306 and 308.
[0074] Like spinal implants 100 and 200, spinal implant 300 also
comprises a nose 311 that tapers as it extends from side wall
surfaces 306 and 308 to the tip of the implant along both the upper
surface 302 and the lower surface 304 of the implant. Spinal
implant 300 further comprises notches 315 formed in both opposite
surfaces of nose 311.
[0075] FIG. 10 is a perspective view of a spinal implant 400
according to still another embodiment. FIG. 11 is a top plan view
of the spinal implant 400 of FIG. 10. And FIG. 12 is a
cross-sectional view of spinal implant 400. Spinal implant 400 is
most similar to spinal implant 300. However, spinal implant 400
comprises an inserter reinforced region 445 and an elongated
inserter opening 440. Inserter reinforced region 445 is configured
to provide enhanced stability and strength for the interface
between an inserter instrument and opening 440. Inserter reinforced
region 445 also allows for accommodating a longer inserter opening
440, such that there is more contact/interface between the
instrument and spinal implant 400.
[0076] Although opening 440 begins at a central location within
fish-tailed recess 430 of spinal implant 400, like spinal implant
300, opening 440 does not extend along the arcuate axis of spinal
implant 400. More specifically, opening 440 is positioned at an
angle of about 25 degrees with respect to the arcuate axis of
spinal implant 400. In preferred embodiments, it is expected that
the angle at which the opening is formed with respect to the axis
of implant 400 will be slightly larger than the corresponding angle
of implant 400. Thus, in some embodiments, this angle may be
between about 5 degrees and about 50 degrees. In some such
embodiments, this angle may be between about 15 degrees and about
50 degrees. In some such embodiments, the angle at which the
opening is formed with respect to the axis of the implant may be
between about 20 degrees and about 30 degrees. Of course, as
inferred above, in some embodiments, the inserter hole/opening may
extend at least substantially along the axis of the implant. In
other words, the angle referenced above may be about zero
degrees.
[0077] It can also be seen in FIG. 12 that opening 440 extends
through side wall surface 408, rather than extending into the
central opening 422 that extends through upper surface 402 and
lower surface 404. However, alternative embodiments are
contemplated in which opening 440 may form a blind hole that is
closed at one end and does not extend all of the way through the
side wall surface 408 of implant 400. It can also be seen in FIGS.
10-12 that opening 422 has been reshaped from the oval shape of
previous embodiments to accommodate reinforced region 445.
Otherwise stated, reinforced region 445 protrudes into the space
that opening 422 would have otherwise occupied.
[0078] Like several of the previously described embodiments, rear
end wall surface 412 comprises a recess 430 that comprises a v
shape formed in a fishtail configuration that may be configured to
directly interface with a spinal installation instrument or to
indirectly couple with an intermediary piece configured to directly
interface with such an instrument.
[0079] Also like several of the previous embodiments, upper and
lower surfaces 402 and 404, respectively, of implant 400 both
comprise a plurality of teeth 420 arranged in rows. Teeth 420
radiate from a focal point positioned along the axis of spinal
implant 400. In addition, spinal implant 400 and its axis extend
along an arcuate path to form a kidney shape. Each of the rows in
which teeth 420 are arranged is at least substantially
perpendicular to both the first side wall surface 406 and the
second side wall surface 408. In addition, like the embodiments
depicted in the previous figures, the spacing between the rows of
teeth decreases from the front end wall surface 410 or nose 411 to
the rear end wall surface 412.
[0080] Unlike the previously described embodiments, spinal implant
400 comprises a single opening 424 formed in side wall surfaces 406
and 408. Like the shape of central opening 422, this is due to the
presence of reinforced region 445 and the elongated inserter
opening 440 formed therein.
[0081] Spinal implant 400 further comprises a nose 411 that tapers
as it extends from side wall surfaces 406 and 408 to the tip of the
implant along both the upper surface 402 and the lower surface 404
of spinal implant 400. Spinal implant 400 further comprises notches
415 formed in both opposite surfaces of nose 411 to, as described
above, facilitate allowing the sidewalls/rails to assist in
positioning the implant during installation.
[0082] FIG. 13 is a perspective view of yet another embodiment of a
spinal implant 500. Spinal implant 500 is also depicted in the top
plan view of FIG. 14. This embodiment comprises many of the same
features and elements of embodiments previously described. For
example, spinal implant 500 comprises an upper surface 502, a lower
surface 504, a first side wall surface 506, a second side wall
surface 508 opposite from surface 506, a front end wall surface 510
comprising a tapered nose 511, and a rear end wall surface 512
opposite from front end wall surface 510.
[0083] Rear end wall surface 512 comprises a v-shaped or fishtail
recess 530 that may be configured to directly interface with a
spinal installation instrument or to indirectly couple with an
intermediary piece configured to directly interface with such an
instrument. Although not shown in FIGS. 13 and 14, spinal implant
500 may also comprise an opening formed in v-shaped recess 530. In
some embodiments, such opening may be threaded so as to allow for
engagement with an inserter tool. This inserter opening may extend
along the arcuate axis of spinal implant 500 or, alternatively, may
extend at an angle with respect to this axis as previously
described. Also, this opening may form a blind hole that is closed
at one end, may extend through central opening 522, or may extend
through one of the side wall surfaces of the implant.
[0084] Like each of the embodiments described above, upper and
lower surfaces 502 and 504 of implant 500 both comprise a plurality
of teeth 520 arranged in rows. Also, as mentioned above, upper
surface 502 comprises an opening 522 that extends through lower
surface 504 and openings 524 are formed in side wall surfaces 506
and 508. Spinal implant 500 further comprises a nose 511 that
tapers as it extends from side wall surfaces 506 and 508 to the tip
of the implant along both the upper surface 502 and the lower
surface 504 of the implant.
[0085] However, instead of the notches described above that were
formed in both opposite surfaces of the nose, spinal implant 500
comprises partial fins 550 positioned on the upper and lower
surfaces of nose 511. It has been discovered that providing fins
550, or any of the alternative fins described herein, may be useful
in facilitating installation of the implant upon which such fins
are positioned. More particularly, such fins may facilitate guiding
the implant in a curved path as it is installed in a patient's
intervertebral space.
[0086] Fins 550 are positioned along only the convex side wall
surface 508. However, other embodiments are contemplated in which
fins are also positioned along concave side wall surface 506. Fins
550 are also only positioned along a portion of front end wall
surface 510 and adjacent nose 511 beyond the first row of teeth
520. In addition, as shown in both FIG. 13 and FIG. 14, fins 550
are contiguous with and extend from the convex surface forming nose
511.
[0087] However, as will be discussed below in connection with other
embodiments, such fins may also extend alongside the teeth across
the entire length of the spinal implant if desired. In addition,
although not depicted in any figures, other embodiments are
contemplated in which fins 550 extend further than they are
depicted as extending in FIGS. 13 and 14, but do not extend across
the entire length of the implant. For example, fins 550 may extend
halfway across the length of spinal implant 500, or any other
length as desired. The upper surface of the upper fin, and the
lower surface of the lower fin, may also taper towards the tip of
nose 511 in a similar manner as nose 511 tapers towards this tip
along both its upper and lower surfaces.
[0088] FIG. 15 is a perspective view of still another embodiment of
a spinal implant 600. FIG. 16 depicts a top plan view of spinal
implant 600. Spinal implant 600 is identical to spinal implant 500
other than the configuration of its fin 650. Unlike fin 550, fin
650 extends across the entire length of spinal implant 600 along
its convex sidewall surface 608. Fin 650 also extends along a
portion of tip 611 that is contiguous with sidewall surface 608. In
some embodiments, an additional fin may extend along concave
sidewall surface 606 if desired, although the depicted embodiment
lacks such a fin.
[0089] In addition, in order to accommodate fin 650 alongside teeth
620 on the convex side of implant 600, a channel 652 is formed in
between fin 650 and teeth 620. In some embodiments, fin 650 may be
configured to extend no further than about the same height as teeth
620. Alternatively, fin 650 may extend beyond the height of the
profile of teeth 620 for certain applications.
[0090] As still other alternatives, the fin may comprise a
discontinuous fin comprising multiple fin portions interspersed by
regions in which no fin is present, and/or regions in which the fin
is shorter or taller. Similarly, the fin(s) may otherwise change in
geometry/shape--such as changes in thickness, height, sharpness,
etc.--at one or more portions/positions along the fin(s).
[0091] Preferably, the fin does not extend all the way to the tip
of the nose of the implant. This may be useful in order to allow
the nose to be used to pry open the intervertebral space or
otherwise facilitate implantation of the device. For example, with
respect to spinal implants 500 and 600, their respective fins 550
and 650 terminate at about the point at which the curvature of the
tip increases such that the distal-most portion of the tip does not
comprise a fin. In addition, although both fins 550 and 650 are
shown extending along the outer surface of the convex sidewall,
other embodiments are contemplated in which the fins may instead be
positioned along an interior surface of the convex sidewall (and/or
the opposite concave sidewall) that defines central opening 622.
However, the positioning shown in the figures (along the outer
surface of the sidewall) is thought to be preferable for most
applications.
[0092] As with several previous embodiments, rear end wall surface
612 of implant 600 comprises a v-shaped or fishtail recess 630 that
may be configured to directly interface with a spinal installation
instrument or to indirectly couple with an intermediary piece
configured to directly interface with such an instrument. Spinal
implant 600 may further comprise an opening 640 formed in v-shaped
recess 630 that may be threaded so as to allow for engagement with
an inserter tool. This opening, as discussed above, may extend
along the arcuate axis of spinal implant 600 or, alternatively, may
extend at an angle with respect to this axis. Also, this opening
may form a blind hole that is closed at one end, may extend through
central opening 622, or may extend through one of the side wall
surfaces of implant 600.
[0093] FIG. 17 depicts an embodiment of a hub 940 comprising an
installation rod 942 configured to be used with certain embodiments
of surgical instruments for installing spinal implants, and to be
coupled with certain embodiments of spinal implants. Hub 940
comprises a handle 945, which may comprise a plurality of knobs
configured to facilitate gripping and rotation by a surgeon.
Installation rod 942 further comprises a distal tip 946.
[0094] As depicted in the close-up view of FIG. 18, distal tip 946
comprises two separate reduced diameter regions--namely, a first
reduced diameter region 947 and a second reduced diameter region
948--and a threaded portion 949 positioned adjacent to the second
reduced diameter region 948. Preferably, reduced diameter region
948 that is positioned adjacent to threaded portion 949 provides
clearance with at least one thread of a threaded hole of a
corresponding implant. This may be useful in providing for
offloading of the stress/forces on this thread or threads.
[0095] As shown in FIG. 18, second reduced diameter region 948
comprises a diameter that is less than the threads of threaded
portion 949. In addition, first reduced diameter region 947
comprises a diameter that is substantially identical to, or
slightly less than, the diameter of the threads of threaded portion
949, such that it can be received in the opening of a threaded
spinal implant hole.
[0096] However, alternative embodiments are contemplated in which
only one reduced diameter region is provided adjacent to the
threaded portion 949. In some such embodiments, the entire portion
of distal tip 946 proximal to second reduced diameter region 948
may be slightly less than or substantially identical to the
diameter of the threads of threaded portion 949.
[0097] It has been discovered that providing a reduced diameter
region adjacent to a threaded tip may provide substantial benefits,
particularly with respect to ceramic spinal implants, such as
silicon nitride ceramic spinal implants, for example. To elaborate,
providing such a reduced diameter region ensures that the highest
forces applied to threads in the spinal implant will be applied to
the strongest threads. This may substantially reduce fractures or
other damage that may otherwise occur with respect to the spinal
implant. In some embodiments and implementations, this
configuration may allow for threaded engagement only with full
threads of the implant, as opposed to partial threads. Since the
threads at the opening of a threaded hole tend to be partial
threads that are less strong, providing a reduced diameter region
immediately adjacent to a threaded tip of an insertion rod may
allow for bypassing engagement with these weaker threads in favor
of engagement of the full, stronger threads that are typically
deeper within the body of the implant. Thus, by using the
principles of the embodiment depicted in FIG. 18, the only threaded
engagement between rod 942 and a threaded opening of a spinal
implant may be positioned at a spaced location from the periphery
of the opening of a threaded hole such that there is no engagement
between rod 942 and the partial threads at the opening of this
hole.
[0098] FIG. 19 depicts embodiments of a spinal implant, an
inserter, and an intermediary piece each positioned in engagement
with one another and specifically depicting the interface between
the installation rod 942 of FIGS. 17 and 18 and a spinal implant
960. As shown in this figure, an inserter 980 is coupled with an
intermediary piece 970, which is positioned in between inserter 980
and spinal implant 960. Intermediary piece 970 comprises a
protrusion positioned on a first side of the intermediary piece
that is configured to mate and fit within corresponding recess
formed within a distal end of inserter 980. Similarly, intermediary
piece 970 comprises a protrusion positioned on an opposite second
side of intermediary piece 970 opposite from the first side, which
mates with a fishtail recess of spinal implant 960.
[0099] In some preferred embodiments, intermediary piece 970
comprises a non-ceramic material, such as PEEK, titanium, or other
such materials known to those of ordinary skill in the art.
[0100] It should be understood that, although intermediary piece
970 is shown as a separate element that is configured to couple
with inserter 980, other embodiments are contemplated in which
intermediary piece 970 is an integral part of inserter 980, or in
which inserter 980 otherwise comprises a shape at its distal end
matching, or similar to, the distal end of intermediary piece
970.
[0101] As best seen from the view of FIG. 19, threaded portion 949
of rod 942 only engages a threaded portion of spinal implant 960
within the body of spinal implant 960. Due to the presence of
reduced diameter region 948, which is preferably unthreaded and set
back from the rear end of spinal implant 960, as shown in FIG. 19,
there is no engagement between the partial threads adjacent to the
opening of the threaded hole of spinal implant 960 and rod 942. In
some embodiments, the threaded section of spinal implant 960 may be
positioned in the thickest part of spinal implant 960 so as to
further facilitate a desirable engagement that reduces the chances
of breakage, particularly when certain ceramic materials are used
to form the implant.
[0102] FIG. 20 depicts further embodiments of a spinal implant
1160, an inserter 1180, and an intermediary piece 1170 each
positioned in engagement with one another. More particularly,
inserter 1180 is coupled with intermediary piece 1170, which is
positioned in between inserter 1180 and spinal implant 1160.
Intermediary piece 1170 comprises a protrusion 1175 positioned on a
first side of intermediary piece 1170 that is configured to mate
and fit within a corresponding recess formed within a distal end of
inserter 1180. Similarly, intermediary piece 1170 comprises a
surface positioned on a second side of intermediary piece 1170
opposite from the first side, which mates with a rear end of spinal
implant 1160.
[0103] It should be understood that, although intermediary piece
1170 is shown as a separate element that is configured to couple
with inserter 1180, other embodiments are contemplated in which
intermediary piece 1170 is an integral part of inserter 1180, or in
which inserter 1180 otherwise comprises a shape at its distal end
matching, or similar to, the distal end of intermediary piece
1170.
[0104] Spinal implant 1160 comprises a rear end that has a
non-symmetrical shape. More particularly, the rear end of spinal
implant 1160 comprises a non-symmetrical fishtail shape. This shape
is formed by a first rounded protrusion 1162 extending from a
lateral side of implant 1160 at the rear end. A second protrusion
1164 may be formed at the opposite lateral side of implant 1160 if
desired. In the depicted embodiment, second protrusion 1164 is
configured to be at least substantially parallel to an interface of
inserter 1180 and/or intermediary piece 1170.
[0105] Thus, as shown in FIG. 20, intermediary piece 1170 comprises
a shape at its distal end that is at least substantially
complementary to that of the rear end of spinal implant 1160 so as
to allow for these two surfaces to mate with one another.
Intermediary piece 1170 therefore comprises a recess 1172 matching
the first protrusion 1162 and an at least substantially planar
surface 1174 configured to match one of the surfaces defining
second protrusion 1164. In the depicted embodiment, surface 1174 is
at least substantially perpendicular to the direction with which
inserter 1180 extends. However, other embodiments are contemplated
in which this need not be the case. For example, in other
contemplated embodiments, second protrusion 1164 may extend into a
concave recess similar to recess 1172 on the opposite side of
recess 1172.
[0106] It can also be seen in FIG. 20 that intermediary piece 1170
comprises a lip 1163 that extends slightly around a lateral surface
of spinal implant 1160. Although, in alternative embodiments, this
lip 1163 may extend along a greater extent of this lateral surface
(in some embodiments the entire length), it has been discovered
that for certain implant materials, such as silicon nitride ceramic
materials, only a very small lip or, as discussed below, in some
cases no lip at all, may be needed in order to provide suitable
stability for a surgical procedure. In this particular embodiment,
lip 1163 does not extend further than the profile of surface 1174
of intermediary piece 1170.
[0107] FIG. 21 depicts still further embodiments of a spinal
implant 1260, an inserter 1280, and an intermediary piece 1270 each
positioned in engagement with one another. More particularly,
inserter 1280 is coupled with intermediary piece 1270, which is
positioned in between inserter 1280 and spinal implant 1260.
Intermediary piece 1270 comprises a protrusion 1275 positioned on a
first side of intermediary piece 1270 that is configured to mate
and fit within a corresponding recess formed within a distal end of
inserter 1280. Similarly, intermediary piece 1270 comprises a
recess positioned on an opposite second side of intermediary piece
1270 opposite from the first side, which mates with a rear end of
spinal implant 1260.
[0108] Spinal implant 1260 differs from spinal implant 1160 in that
the rear surface of spinal implant 1260 comprises a v-shaped
protrusion. This protrusion is formed from surface 1262 and surface
1264, both of which are at least substantially flat. Also, this
protrusion is non-symmetrical. More particularly, surface 1262 is
longer than surface 1264. Non-symmetrical mating surfaces, such as
are present in spinal implants 1160 and 1260, may be useful for a
variety of reasons. For example, a non-symmetrical surface may be
useful to ensure that the implant is engaged with an intermediary
piece or inserter in the desired position only. In other words, if
you turn the implant upside down, it will not properly engage with
the complementary mating surface on the inserter or intermediary
piece.
[0109] This lack of symmetry may also be present on the
intermediary piece. For example, as shown in FIG. 21, intermediary
piece 1270 comprises a protrusion 1275 that is not centered with
respect to a corresponding inserter 1280. Thus, intermediary piece
1270 may only be correctly engaged with inserter 1280 if the right
side of intermediary piece 1270 is positioned upwards.
[0110] Intermediary piece 1270 also comprises a v-shaped recession
that is non-symmetrical and that is configured to engage the
v-shaped protrusion on spinal implant 1260. More particularly,
intermediary piece 1270 comprises a v-shaped recess defined by a
first flat surface 1272 and a second flat surface 1274 angled with
respect to the first flat surface 1272. Surface 1272 is
complementary to surface 1262 of implant 1260 and surface 1274 is
complementary to surface 1264 of implant 1260, as shown in FIG.
21.
[0111] It can also be seen in FIG. 21 that intermediary piece 1270
differs from intermediary piece 1170 in that it is configured to
engage with spinal implant 1260 without extending beyond the
profile of spinal implant 1260 immediately adjacent to intermediary
piece 1270. In other words, the opposing lateral surfaces of
intermediary piece 1270 are aligned with the opposing lateral
surfaces of spinal implant 1260 immediately adjacent to
intermediary piece 1270 when spinal implant 1260 is engaged with
intermediary piece 1270. In some embodiments, the distal portion of
an inserter may alternatively, or additionally, be similarly
configured to avoid extending beyond the profile of the spinal
implant immediately adjacent to the inserter. In some embodiments,
the inserter and/or intermediary piece may also, or alternatively,
be configured such that the corresponding implant does not extend
beyond the height of the inserter and/or intermediary piece. Thus,
some embodiments may be configured such that the implant does not
extend beyond the profile of the distal portion of the inserter
and/or intermediary piece in any view, including an upper view and
a side view.
[0112] Although in this particular embodiment, the opposing lateral
surfaces of spinal implant 1260 are at least substantially aligned
with the end of the inserter or intermediary piece, alternative
embodiments are contemplated in which the opposing lateral surfaces
of spinal implant 1260 are less than the corresponding opposing
surfaces of the inserter or intermediary piece. In other words, the
inserter and/or intermediary piece may comprise a width at a distal
end that is greater than or equal to the corresponding width of the
spinal implant to be used with the inserter/intermediary piece.
[0113] Of course, alternative embodiments are contemplated in which
this same feature may be obtained without providing an intermediary
piece. For example, an inserter may be provided having a
shape/surface at its distal end identical or similar to the distal
surface of an intermediary piece without need for providing the
intermediary piece.
[0114] Spinal implant 1260 also comprises a portion 1265 positioned
along a rear portion of its top surface that lacks teeth, as shown
in FIG. 21. This may be useful for certain applications in order to
preserve desired structural integrity for certain procedures.
However, other embodiments, such as spinal implant 1160 of FIG. 20,
may comprise teeth that extend all the way to the rear end of the
implant. In some embodiments, this smooth portion 1265 may comprise
a thickness at least substantially identical to the maximum
thickness of the implant 1260 at the tips of the teeth.
[0115] FIG. 22 depicts three additional embodiments of spinal
implants--namely, spinal implants 1300, 1400, and 1500. These three
spinal implants vary in size and in the angling of their respective
inserter holes--inserter holes 1340, 1440, and 1540, respectively.
More particularly, inserter hole 1340 extends at an angle "A" with
respect to a central axis of implant 1300, inserter hole 1440
extends at an angle "B" with respect to a central axis of implant
1400, and inserter hole 1540 extends at an angle "C" with respect
to a central axis of implant 1500.
[0116] In some preferred embodiments and/or systems incorporating
multiple spinal implants of different sizes, these angles become
smaller as the size of the implant increases. Thus, with regard to
the three embodiments depicted in FIG. 22, angle A is greater than
angle B and angle B is greater than angle C. This may be useful for
keeping the implant/inserter profile within a maximum width to
allow for inserting any of the various implants within a tube of a
given diameter.
[0117] In some embodiments, for an implant having a 10.times.27 mm
profile (width v. length), angle A may be between about 25 and
about 35 degrees. In some such embodiments, angle A may be about 30
degrees. In some embodiments, for an implant having a 10.times.30
mm profile, angle B may be between about 23 and about 33 degrees.
In some such embodiments, angle B may be about 28 degrees. In some
embodiments, for an implant having a 10.times.33 mm profile, angle
C may be between about 20 degrees and about 30 degrees. In some
such embodiments, angle C may be about 25 degrees. In some
embodiments, the angle (A/B/C) of the inserter hole may therefore
decrease at least substantially in proportion to an increase in
length of the implant and/or at least substantially in proportion
to a decrease in the radius of curvature of the implant.
[0118] FIG. 23 depicts other alternative embodiments of a spinal
implant 1660, an inserter 1680, and an intermediary piece 1670 each
positioned in engagement with one another. More particularly, this
figure depicts the interface between an alternative embodiment of
an installation rod 1640, intermediary piece 1670, and spinal
implant 1660.
[0119] Installation rod 1640 comprises a distal tip 1641 comprising
a knob or increased diameter region relative to an adjacent reduced
diameter region--namely, reduced diameter section 1642. Reduced
diameter section 1642 may be configured so as to have a diameter
that is less than a minor diameter of the threads of adjacent
threaded section 1643 in some embodiments. In some embodiments,
reduced diameter section 1642 may also, or alternatively, be
configured so as to have a diameter that is less than a diameter of
the installation rod 1640 immediately adjacent to the threaded
section 1642 on the opposite side (i.e., proximal of the threaded
section 1642).
[0120] In some embodiments, knob 1641 may be configured to extend
all of the way through the opening in spinal implant 1660 through
which installation rod 1640 extends, as shown in FIG. 23. In some
embodiments, knob 1641 may comprise a flexible material such that
at least a portion of knob 1641 extends beyond the perimeter of
this opening after installation rod 1640 has extended through this
opening. In some embodiments, one or more engagement members may be
configured to be deployed within an opening 1622 that extends
between upper and lower surfaces of spinal implant 1660 so as to
facilitate a more secure engagement between installation rod 1640
and spinal implant 1660.
[0121] Other embodiments are contemplated in which at least a
portion of installation rod 1640 may be configured to expand once
it has been positioned within the opening in spinal implant 1660
through which installation rod 1640 extends. This may facilitate a
friction fit between installation rod 1640 and this opening, which
may negate the need for providing threads.
[0122] Adjacent to reduced diameter section 1642 is a threaded
portion 1643, which is configured to be threaded with a female
threaded region 1663 in spinal implant 1660. Reduced diameter
section 1642 may be configured to facilitate introduction of
threaded portion 1643 into female threaded region 1663 of spinal
implant 1660. In certain preferred embodiments, female threaded
region 1663 is spaced apart from both opposite ends of the opening
through which installation rod 1640 is received. As discussed in
greater detail elsewhere, this may be useful in connection with
spinal implants comprised of certain materials, such as silicon
nitride ceramic and other ceramic materials and/or materials with
similar properties, which may be prone to fracturing at certain
points during installation.
[0123] An unthreaded section 1644 is positioned adjacent and
proximal to threaded portion 1643. At least a portion of unthreaded
section 1644 may be configured to be tightly engaged with at least
a portion of the opening through which installation rod 1640 is
received. In other words, in some embodiments, unthreaded section
1644 and at least a portion of the opening through which
installation rod 1640 is received that is proximal to female
threaded region 1663 may have a diameter at least substantially
matching the minor diameter of threaded portion 1643. In this
manner, the implant and accompanying installation instrumentation
may be configured such that the threaded connection between the
implant and the rod is positioned internally so as to avoid
unwanted forces caused by the threads. In alternative embodiments,
unthreaded section 1644 may have a diameter that is slightly less
than that the portion of the opening through which installation rod
1640 is received that is proximal to female threaded region 1663 so
as to provide for some clearance between the installation rod 1640
and this opening along this region. However, again, preferably the
threads on threaded portion 1643 and female threaded region 1663 do
not extend all of the way to the proximal end of the opening
through which installation rod 1640 extends.
[0124] The proximal part of the opening through which installation
rod 1640 extends preferably comprises an expanded region 1665,
which may further facilitate desired coupling between installation
rod 1640 and spinal implant 1660 by providing clearance for the
threads on threaded portion 1643. In the depicted embodiment,
expanded region 1665 is defined by a frustoconical shape that
tapers so as to expand the diameter of this opening towards the
proximal end of the opening. However, other embodiments are
contemplated. For example, in some embodiments, other shapes may be
used, as long as at least a portion of the proximal portion of the
opening is wider than the portion immediately adjacent to the
threaded region 1663.
[0125] A second unthreaded section 1645 may be positioned adjacent
to, and proximal of, unthreaded section 1644 of installation rod
1640. Second unthreaded section 1645 may comprise a larger
cross-sectional diameter than unthreaded section 1644. Second
unthreaded portion 1645 may be configured to engage at least
primarily, if not wholly, with intermediary piece 1670, as shown in
the figure. The transition between unthreaded section 1644 and
second unthreaded section 1645 may comprise a taper, as illustrated
in FIG. 23. Alternatively, a more abrupt transition may be formed
between unthreaded section 1644 and second unthreaded section
1645.
[0126] Similarly, the main body of installation rod 1640 may have a
cross-sectional diameter that is greater than second unthreaded
section 1645, which main body may be configured to at least
primarily, if not wholly, be engaged with inserter 1680. Likewise,
the transition between second unthreaded section 1645 and the main
body of installation rod 1640 may, but need not, comprise a
taper.
[0127] Providing a reduced diameter region adjacent to a threaded
tip, providing a threaded section within an opening configured for
engagement with an installation rod such that it is spaced apart
from the proximal, periphery of the opening, providing a reduced
diameter section adjacent to one or more sides of a threaded
section of an installation rod, and/or providing an expanded
region, such as expanded region 1665, at the proximal end of such
an opening may provide substantial benefits, particularly with
respect to ceramic spinal implants, such as silicon nitride ceramic
spinal implants and the like. Without being limited by theory, one
or more of these features may ensure that the highest forces
applied to threads in the spinal implant will be applied to the
strongest threads and/or will only be applied to threads that are
set back from the weakest part of the opening. This may
substantially reduce fractures or other damage that may otherwise
occur with respect to the spinal implant.
[0128] However, other embodiments are contemplated in which a
threaded section need not be provided. For example, some
embodiments may be configured to provide for engagement between the
rod and the implant that is spaced apart from an edge and/or
periphery of the implant by way of a compression or friction fit,
for example, or another engagement feature that engages the rod and
the implant without threads. Preferably such engagement does not
apply forces, or at least applies reduced forces, to the rear
portion of the hole to engage the rod. In this manner, the forces
applied to the relatively weak portions of the implant may be
reduced to avoid or at least reduce the chances for
cracking/breaking, which, as mentioned above, may be particularly
useful in connection with certain ceramic implants that may be
prone to such problems.
[0129] FIG. 24 illustrates another embodiment of a spinal implant
1700. Spinal implant 1700 comprises an upper surface 1702, a lower
surface 1704, a first side wall surface 1706, a second side wall
surface 1708 opposite from surface 1706, a front end wall surface
1710 comprising a nose, and a rear end wall surface 1712 opposite
from front end wall surface 1710. Rear end wall surface 1712
comprises a v-shaped recess 1730. An opening 1740 is positioned
within recess 1730. In the depicted embodiment, opening 1740 is
positioned centrally with respect to recess 1730.
[0130] Like several of the previously-discussed embodiments, the
v-shaped recess 1730 of spinal implant 1700 may be configured to
directly interface with a spinal installation instrument or to
indirectly couple with an intermediary piece configured to directly
interface with such an instrument. However, unlike some of the
previously-discussed embodiments, recess 1730 does not extend all
of the way between sidewall surfaces 1706 and 1708. Instead, recess
1730 is spaced apart from both sidewall surface 1706 and sidewall
surface 1708. However, recess 1730 does extend all of the way
between upper surface 1702 and lower surface 1704.
[0131] Upper and lower surfaces 1702 and 1704 both comprise a
plurality of teeth 1720 arranged in rows. Teeth 1720 may be
configured as previously described in connection with other
embodiments. Similarly, other features disclosed in connection with
other embodiments may be included with spinal implant 1700, or with
any other embodiment disclosed herein without such feature(s). For
example, spinal implant 1700 may comprise, notches, such as notches
215 in spinal implant 200, formed in one or both opposite surfaces
of its nose. Similarly, spinal implant 1700 may comprise, in
alternative embodiments, one or more fins, such as fins 550 as
depicted on spinal implant 500.
[0132] Any methods disclosed herein comprise one or more steps or
actions for performing the described method. The method steps
and/or actions may be interchanged with one another. In other
words, unless a specific order of steps or actions is required for
proper operation of the embodiment, the order and/or use of
specific steps and/or actions may be modified.
[0133] Throughout this specification, any reference to "one
embodiment," "an embodiment," or "the embodiment" means that a
particular feature, structure, or characteristic described in
connection with that embodiment is included in at least one
embodiment. Thus, the quoted phrases, or variations thereof, as
recited throughout this specification are not necessarily all
referring to the same embodiment.
[0134] Similarly, it should be appreciated that in the above
description of embodiments, various features are sometimes grouped
together in a single embodiment, figure, or description thereof for
the purpose of streamlining the disclosure. This method of
disclosure, however, is not to be interpreted as reflecting an
intention that any claim require more features than those expressly
recited in that claim. Rather, inventive aspects lie in a
combination of fewer than all features of any single foregoing
disclosed embodiment. It will be apparent to those having skill in
the art that changes may be made to the details of the
above-described embodiments without departing from the underlying
principles set forth herein. The scope of the present invention
should, therefore, be determined only by the following claims.
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